查询词典 a beam of light

Secondly, three kinds of mathematics model of optical vortex beams were introduced here. Then the propagation dynamics of optical vortex beams through the non-axis symmetry system is studied, this chapter includes the introduction of the symmetry vortex beam and the non- symmetry vortex beam, the deduction of the Collins diffract integral formula for the non-axis symmetry system, and the transformation of the vortex beam passing through the non-axis symmetry system has been described by using the numerical simulation. Then the general calculation for the orbit momentum of vortex beams, the matrix form for the orbit momentum of vortex beams, and the photon method to describe the orbit momentum of vortex beams are also introduced here. Finally, the interference about optical vortex beams was studied.

本文对涡旋光束进行了较为全面的介绍和研究，主要内容包括：（1）光学涡旋光束的基本理论，主要是介绍了单个光学涡旋光束在柱坐标中的一些表征，涡旋光束的奇异相位和光学涡旋的相位结构；（2）光学涡旋光束的三种数学模型；（3）光学涡旋光束在非轴对称光学系统中的传播动力学，其中介绍了对称涡旋光束与非对称涡旋光束，推导了非轴对称光学系统的 Collins 衍射积分公式，并利用计算机模拟图描述了对称涡旋光束经过非轴对称光学系统后涡旋形态的改变；（4）涡旋光束轨道角动量的一般计算，涡旋光束轨道角动量的矩阵形式，光子法描述涡旋的轨道角动量；（5）涡旋光束的干涉。

In this paper, draw the idea of beam unit, the bias along the vertical box is divided into a number of oblique beam. On the basis of analysis of the displacement, through positive and oblique coordinate transformation relations, and directly built on the oblique coordinate system to describe the methods of displacement unit space. With potential energy principle is derived in oblique beam element stiffness matrix and the establishment of the finite element formulation. The preparation process of the finite element analysis is used to verify the structure of bias.

本文吸取梁段单元的思想，将斜交箱梁沿纵向划分为若干斜梁段，在位移分析的基础上，通过正、斜交坐标转换关系，直接建立在斜交坐标系内描述单元空间位移的方法，用势能驻值原理推导斜梁单元刚度矩阵并建立其有限单元列式，利用编制的有限元程序进行斜交结构的分析。

In order to use electron beam in brazing of precise structures and thermo-sensitive materials,accommodating every kinds of curve brazing seams,a vacuum electron beam brazing temperature closed loop control system was developed using PID controller,electron beam scanning track editing and on-line adjusting technologies,real-time acquisition and handling of brazing temperature.

为了将电子束应用于精密构件及热敏感性材料钎焊，以适应复杂形状曲线钎焊缝的要求，采用电子束扫描轨迹编辑及在线调节、钎焊温度实时采集及PID控制器构建真空电子束钎焊温度闭环控制系统。

The invention also provides a method for producing the laser beam focusing integer type parabolic mirror formed in one piece using a rotary type high accuracy machine tool, with features of simple technique, increased capacity of reflector for proofing the high power laser beam and heat-sinking capability, and improved focusing quality of laser beam.

本发明还提供制造所述激光光束聚焦整型抛物面镜的方法，该方法利用回转型高精车机床一次成型加工，制造工艺简单，可提高反射镜耐高功率激光束的能力以及散热能力，改善激光束的聚焦质量。

When the probe rotates a circle, the picture of the beam profile in two perpendicular directions is given, the position of the beam in the beam line and its intensity are also displayed.

本截面仪采用磁耦合静密封代替旋转密封，结构简单、使用方便。

Combining with the National Natural Science Foundation ofChina(No.50478032), following researches were done in this thesis: 1 The variation regularity of the ultimate anti-bending capacity of therectangular-sectioned beam with different corrosion has been obtained through thequalitative analysis of 48 beams (32 corroded beams and 12 comparing beams) withaccelerated corrosion; 2 The conclusion has been obtained that the strain of corroded steel bar andconcrete no longer fit in with the assumption of plane section through the analysis ofthe strain data, the strain relation of steel bar and concrete in the mid-span section ofvariously corroded beams at ultimate has been obtained. Through the building of newgeometric relation, the expression of the height of compressive area in the corrodedbeam with rectangular section has been deduced, and the formula with corrosion rateas the main variable for the anti-bending capacity of the corroded concrete beam hasbeen suggested and verified by experiment.; 3 The influence of steel bar corrosion and the concrete regression to the flexureductility coefficient of the corroded structure component has been analyzed. Based onthe relation of steel bar and concrete at yield and ultimate, the expression for theflexure at yield and ultimate of corroded reinforced concrete beam, and the model forthe calculation of the flexure ductility has been built.

本文结合国家自然科学基金项目(50478032)"既有钢筋混凝土桥梁时变可靠度研究"，主要进行了以下研究工作： 1通过对48根快速锈蚀钢筋混凝土矩形截面梁(32根锈蚀梁和12根对比试验梁)数据的定性分析，得到了不同锈蚀率下，锈蚀钢筋混凝土矩形截面梁极限抗弯承载力的变化规律； 2通过对应变数据的分析，论证了锈蚀构件钢筋和混凝土的应变不再符合平截面假定的结论，并通过回归分析得出了不同锈蚀率的螺纹钢筋梁和光圆钢筋梁在极限弯矩作用下，跨中截面处钢筋应变和钢筋处混凝土应变的关系，通过构造新的几何关系，得出了锈蚀钢筋混凝土矩形截面梁计算受压区高度的表达式，既而得出了以锈蚀率为主要变量的锈蚀钢筋混凝土矩形截面梁的正截面抗弯计算建议公式，并通过试验数据加以验证； 3分析了钢筋锈蚀和混凝土劣化对锈蚀构件曲率延性系数的影响，结合钢筋屈服和极限弯矩两种状态下钢筋和混凝土的应变关系，分别得到了锈蚀钢筋混凝土矩形截面梁屈服曲率和极限曲率的计算表达式；既而推导出曲率延性系数的计算模型。

In the experiments,beam bugs were used to detect the beam currents and the beam positions,and the Cerenkov radiation generated by the electron beams interacting with a quartz plate was used to get the information of the beams.

在实验中，电子束流强度和电子柬心运动用电阻环进行测试，而电子束和石英玻璃的相互作用产生的契仑科夫辐射用来给出电子束包络和发射度信息。

In order to study initial stress and ring force transfer between steel plates and concrete in the numerical analysis of RC beam strengthened by bonding steel plates,8 scale-down models of RC beam were manufactured,their loaded whole processes were analyzed by using surface-surface contact analysis method and "birth and death" element method,and a numerical analysis method of strengthening RC beam with initial stress was proposed.

0引言钢板加固钢筋混凝土结构已在国内外受到广泛应用和研究，并且已获得了大量的研究成果，但成果主要来源于室内模型试验。由于受到试验规模的制约，目前所取得的研究成果，特别是试验成果还带有较大的片面性，不能系统地反应其真实的自然规律[1-3]。

Radius variation of image beam waist due to spherical aberration, which varies with the position of objective beam waist, and optical system focus is analyzed with the form of curve. At last,a design example of optical system used for laser plume attenuation testing system is given to illustrate the effect of spherical aberration on the image beam waist.

本文还提出了在设计过程中存在的球差对激光束像方束腰的影响，对其进行了理论分析，并给出了数学模型，总结出高斯光束的像方束腰半径与物方束腰位置、光学系统焦距之间的关系，并对本光学系统的设计进行了验算。

It must generate a sufficient beam separation and clear head and tail for the beam pulse. Otherwise, it will induce a large amount of beam losses.

它必须要产生充分的束流分离和干净的脉冲头尾，否则，将带来很大的束流损失。

Article 144 The Government of the Hong Kong Special Administrative Region shall maintain the policy previously practised in Hong Kong in respect of subventions for non-governmental organizations in fields such as education, medicine and health, culture, art, recreation, sports, social welfare and social

第一百四十四条香港特别行政区政府保持原在香港实行的对教育、医疗卫生、文化、艺术、康乐、体育、社会福利、社会工作等方面的民间团体机构的资助政策。原在香港各资助机构任职的人员均可根据原有制度继续受聘。

Small wonder, then, that the Chinese spend more in the shop than any other group of foreign visitors do .

这样的小惊喜，使中国顾客比任何国家的人消费得更多。